Tokyo earthquake reports - Japan prelim magnitude 7.3 - off Fukushima (Tsunami Imminent)

In case this hasn't been posted yet.

This is live.

originally posted by: Vasa Croe

The inspection has apparently been suspended at the reactor.

Sounds a bit worrying .. has the inspection finished or is it too risky for them to carry on with the inspection

a reply to: jadedANDcynical
I think the foreshock was 7.2Mw or thereabouts, about two days before the main shock. But there were at least 3 aftershocks in the mid to high 7 Mw range.

I get what you're saying about the clustering concept. I think they still generally say there just isn't enough data yet to be more definitive about that, because megaquakes are (thankfully!) so rare. But there is a certain logic to the idea, both from the point of view of remote triggering (maybe) and also knock-on effects on other sections of a main subduction zone.

Trouble is, we have no way of knowing if a quake is a foreshock until a bigger one happens in the same region.

And also, there is the Boso triple junction region south of Yokohama that scientists have been "expecting" to let go for years. Hopefully this event has not shaken things up enough to have any serious effects on that.

The way they are recording it the time stamp keeps moving. The wave action on the shoreline in front of the plants can be seen in here (currently) at about the -55 minute mark.

originally posted by: mzinga
I believe the size of the Tsunami is related to the displacement of the sea floor and not the magnitude of the quake. I'm not positive, but I do not believe those are always directly related.

I believe your statement is dead on

a reply to: reldra
My opinion FWIW is that in this case, I'd take JMA's assessment over USGS's. It's in JMA's back yard, after all. As for USGS, they still have that quake at 6.9 Mw and 11.3 km depth.

a reply to: ThePeaceMaker

More likely if they are having trouble with sensitive and critical systems due to the quake, it is an all hands on deck kind of situation, so even if it isn't technically immediately dangerous, the last thing anyone needs is for VIPs who don't know what they're doing to be there and in the way. The people needed to babysit them would be much more useful in their day-to-day or emergency roles.

An inspection can always be finished later on when no one is trying to quickly get things back in order.

originally posted by: JustMike
a reply to: reldra
My opinion FWIW is that in this case, I'd take JMA's assessment over USGS's. It's in JMA's back yard, after all. As for USGS, they still have that quake at 6.9 Mw and 11.3 km depth.

I am with you on this. They are not reporting the same and I would take the local news source over USGS.

They are claiming the pump operating the flow of coolant at the Fukushima reactor number three cooling pool has been restored.

Assuming power was cut off due to power interruption at the plant during the earthquake, the resumption could be due to emergency back up power or restoration of primary power, depending on who you believe. NHK news outlet is owned by Tepco...

USGS reporting smaller aftershocks off the Fukushima coast of around 4 - 5 mag

USGS earthquake map

Obviously not JMA info though

a reply to: JustMike

Yeah, I thought I was a bit high on the foreshock guesstimate, but I knew it was in the 7ish range.

I remember also that the Tohoku quake puzzled scientists as it is not the one they were expecting to let go and be the next mega quake in Japan; as you noted, it is in a different spot entirely.

I also recall our conversations regarding triggered quakes resulting from quakes far removed from the quake triggered.

I wonder if the M8 algorithm by Keilis-Borok has been applied to this region and what the result of said application might have been?

a reply to: mzinga
The area of sea floor displaced (and by how much vertically up or down) and along what length, forms part of the primary calculation to determine the quake's magnitude, especially in the moment magnitude (Mw) scale where energy released is a major consideration. Generally speaking, higher magnitude quakes of the right type (especially subduction) tend to produce bigger tsunamis in terms of both their wavelength and extent, and hence higher cumulations along longer regions of shore line.

True, a smaller magnitude quake can produce a large, reasonably localized tsunami, but there is usually a fair correlation between quake magnitude and tsunami size.

Adding for review. A screen shot of the tank farm showing wet ground around some of the tanks. Whether that ground is wet from rain or water sloshing out of the tanks during a 7+ earthquake is up for interpretation.

a reply to: jadedANDcynical
I don't know about that specific region re the M8 algorithm, but Kossobokov, Maeda and (I think) Uyeda did a study on the Kobe quake (of 1995) and it fitted the M8-MSc prediction model. I'd have to dig to find my copy but I'm pretty sure their published study would still be online.

Anyway, the good news right now is that it seems the worst of the tsunami risk from today's event has passed. Hopefully they will take care of whatever cooling/water problems they had at the reactor plants and have learned a bit more about what they need to do to prepare better for the next really big one.

a reply to: intrptr

They said it is a cold and rainy day.

We're still a bit away from high tide, which I think is the reason for the prolonged warning, because while it's probable the highest wave heights have already reached shore, subsequent waves, even if somewhat smaller, could be effectively higher due to high tide. High tide I believe will be in about 17 minutes as of the time of this post.

I also always assume the worst to be on the safe side, so I too am going with JMA right now over USGS. It sounds like cooling has been restored at the plant, and like it's unlikely larger waves will hit. But I don't expect the warning to be lifted until after high tide and after a decreasing wave height is detected. It's unlikely we'll see any major onshore tsunami damage this time, but better safe than sorry.

Peace.

a reply to: auroraaus
USGS would probably be getting a lot of their data via JMA in this case.

If you go to JMA's Earthquake Information page, you can get pretty good data on the latest quakes. In English.

Oh gosh, I hope the people got to higher ground in time!

I've been switching back and forth from CNN to Fox and I'm not hearing anything about it! Why is that?

a reply to: JustMike

Thanks again, JustMike! Perhaps the world should agree to not build any Nuclear Plants near fault zones. There's enough land on this planet to do that.

If I remember correctly, the prevailing winds would carry any radiation leakage across the Pacific and into the West Coast of the U.S.. Or, maybe that was just the ocean current. Either way, parts of the U.S.A. could face a catastrophe that dwarfs the Pearl Harbor attack, courtesy of Japan, once again.

In other quake news a 6.3 mag just hit off the coast of New Zealand (north Island near Palmerston north) at about a depth o f 37kms

Just sticking that there for any interested parties.